Vertical pictures are getting distorted in Adobe Portfolio

So I shoot everything on my Fuji X100V and directly export it to my pc from the sd card. All pictures are vertical, same aspect ratios. I load them into Bridge to sort them, move them afterwards into folders to have the final pictures. The pictures are saved as JPGs, approx. 12MB per picture. I then upload them as a grid into Portfolio and no matter what settings I use, this is what happens: 

When I click on the picture, everything looks fine, but in the grid pictures always get distorted. If I upload pictures one by one, the look good, but they are displayed too big for my liking, I would like to have a grid of 5 pictures next to eachother but I really am freaking out, because I cant find a solution. 

Pls help:)